1. Field of the Invention
The present invention relates to a pickup frame made of a composite material including a synthetic resin and a metal, an optical pickup device including such a pickup frame, and an optical information recording/reproduction apparatus including such an optical pickup device.
2. Description of the Related Art
As a means for reading an information signal that is stored on an optical disc, which is being rotated by an optical disc drive, by irradiating the signal storage side of the disc with light or a means for writing information on the optical disc, an optical pickup device is built in a recording/reproduction apparatus.
Recently, an optical information recording/reproduction apparatus (or an optical drive) including such an optical pickup device is built in mobile personal computers (which are sometimes called “mobile PCs”) more and more often. And the more popular such PCs have become, the handier they should come in. Specifically, their handiness is rated by their size (particularly their thickness) and their weight. That is to say, the smaller, thinner and lighter such a PC, the better. And an optical pickup device, which is one of essential components of an optical drive, is also required to meet those demands. On top of that, the optical pickup device also needs to have sufficiently high rigidity and rather high reliability under various harsh external environments, even though these requirements are contradictory to those downsizing trends. That is to say, the optical pickup device should maintain sufficient rigidity and operate with good stability even when exposed to a rather high or low temperature or high and low temperatures alternately a number of times. And the pickup frame, which is one of the main members of the optical pickup device, is a main factor that will determine its size and weight. That is why the following description will be focused on such a pickup frame.
The housing of popular optical drives built in mobile PCs often has a thickness (or height) of 12.7 mm or 9.5 mm.
An optical drive with a thickness of 12.7 mm adopts a pickup frame in which both of bearing portions arranged at both ends of an optical pickup device are often formed as integral parts of a single member by performing a metal die casting process. Meanwhile, some drives may adopt a pickup frame in which those portions are all formed out of a synthetic resin as respective parts of a single member. In those pickup frames, a light emitter and a photodetector are supported with a holder. And part of an optical element that changes the optical paths is also supported on such a pickup frame.
On the other hand, an optical drive with a thickness of 9.5 mm adopts a pickup frame in which both of bearing portions arranged at both ends of an optical pickup device are formed as respective parts of a single member by performing a die casting process on a metal such as aluminum or magnesium. In such a pickup frame, a light emitter and a photodetector are supported with a holder. And part of an optical element that changes the optical paths is also supported on such a pickup frame.
Also proposed is a pickup frame in which a supporting base, where both of bearing portions arranged at both ends of an optical pickup device are formed out of a synthetic resin as respective parts of a single member, and a metallic optical base that supports a light emitter, a photodetector and an optical element to change optical paths are bonded together with an adhesive (see Patent Document No. 1 (Japanese Patent Application Laid-Open Publication No. 2008-171498).